scsi: ufs: Introduce UFSHCD_QUIRK_PRDT_BYTE_GRAN quirk

Some UFS host controllers like Exynos uses granularities of PRDT length and
offset as bytes, whereas others use actual segment count.

Link: https://lore.kernel.org/r/20200528011658.71590-5-alim.akhtar@samsung.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
Signed-off-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufshcd.c

@@ -2168,8 +2168,14 @@ static int ufshcd_map_sg(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 		return sg_segments;
 
 	if (sg_segments) {
-		lrbp->utr_descriptor_ptr->prd_table_length =
-			cpu_to_le16((u16)sg_segments);
+
+		if (hba->quirks & UFSHCD_QUIRK_PRDT_BYTE_GRAN)
+			lrbp->utr_descriptor_ptr->prd_table_length =
+				cpu_to_le16((sg_segments *
+					sizeof(struct ufshcd_sg_entry)));
+		else
+			lrbp->utr_descriptor_ptr->prd_table_length =
+				cpu_to_le16((u16) (sg_segments));
 
 		prd_table = (struct ufshcd_sg_entry *)lrbp->ucd_prdt_ptr;
 
@@ -3518,11 +3524,21 @@ static void ufshcd_host_memory_configure(struct ufs_hba *hba)
 				cpu_to_le32(upper_32_bits(cmd_desc_element_addr));
 
 		/* Response upiu and prdt offset should be in double words */
-		utrdlp[i].response_upiu_offset =
-			cpu_to_le16(response_offset >> 2);
-		utrdlp[i].prd_table_offset = cpu_to_le16(prdt_offset >> 2);
-		utrdlp[i].response_upiu_length =
-			cpu_to_le16(ALIGNED_UPIU_SIZE >> 2);
+		if (hba->quirks & UFSHCD_QUIRK_PRDT_BYTE_GRAN) {
+			utrdlp[i].response_upiu_offset =
+				cpu_to_le16(response_offset);
+			utrdlp[i].prd_table_offset =
+				cpu_to_le16(prdt_offset);
+			utrdlp[i].response_upiu_length =
+				cpu_to_le16(ALIGNED_UPIU_SIZE);
+		} else {
+			utrdlp[i].response_upiu_offset =
+				cpu_to_le16(response_offset >> 2);
+			utrdlp[i].prd_table_offset =
+				cpu_to_le16(prdt_offset >> 2);
+			utrdlp[i].response_upiu_length =
+				cpu_to_le16(ALIGNED_UPIU_SIZE >> 2);
+		}
 
 		ufshcd_init_lrb(hba, &hba->lrb[i], i);
 	}

drivers/scsi/ufs/ufshcd.h

@@ -537,6 +537,12 @@ enum ufshcd_quirks {
 	 * enabled via HCE register.
 	 */
 	UFSHCI_QUIRK_BROKEN_HCE				= 1 << 8,
+
+	/*
+	 * This quirk needs to be enabled if the host controller regards
+	 * resolution of the values of PRDTO and PRDTL in UTRD as byte.
+	 */
+	UFSHCD_QUIRK_PRDT_BYTE_GRAN			= 1 << 9,
 };
 
 enum ufshcd_caps {